moogvcf2

Description

A digital emulation of the Moog diode ladder filter configuration.

Syntax

ares moogvcf2 asig, xfco, xres [,iscale, iskip]

Initialization

iscale (optional, default=0dBfs) -- internal
scaling factor, as the operation of the code requires the signal
to be in the range +/-1. Input is first divided by
iscale, then output is mutliplied by
iscale.

iskip (optional, default=0) -- if non zero
skip the initialisation of the filter.

Performance

asig -- input signal

xfco -- filter cut-off frequency in
Hz. which may be i-,k-, or a-rate.

xres -- amount of
resonance. Self-oscillation occurs when xres
is approximately one. May be a-rate, i-rate, or k-rate.

moogvcf2 is a digital emulation of the Moog
diode ladder filter configuration. This emulation is based loosely
on the paper “Analyzing the Moog VCF with Considerations for
Digital Implementation” by Stilson and Smith (CCRMA). This
version was originally coded in Csound by Josep Comajuncosas. Some
modifications and conversion to C were done by Hans Mikelson and then
adjusted.

moogvcf2 is identical to moogvcf, except that the
iscale parameter defaults to 0dbfs instead of 0, guaranteeing that amplitude will usually be OK.

Examples

Here is an example of the moogvcf2 opcode. It uses the file moogvcf2.csd.